Digital televisions (TVs) comprising wide-screen, high-image quality displays have prevailed. In addition to viewing of high-image quality broadcast programs by digital TV broadcast, and viewing of additional information services by data broadcast, the needs for viewing still images which are sensed by digital cameras and are output onto paper media so far upon appreciation on the wide-screen of a digital TV are increasing.
Still images sensed by a digital camera are sent to a digital TV via an information storage medium such as a memory card or the like, and are displayed on the display screen of a digital TV via an image display function of the digital TV. The viewing method of image data includes two modes, i.e., a mode of viewing individual image data by user's operations, and a mode of displaying image data which belong to a designated group under the TV control, i.e., a slide show mode.
As a simple method of starting a slide show by designating an image data group, one of TV channels is assigned to start viewing of a slide show by the same operation as channel selection of TV broadcast (for example, Japanese Patent Laid-Open No. 2002-218331).
When designation of an image data group which is to undergo a slide show is assigned to one of TV channels, and the slide show is started by channel selection, there are two operation methods as in the conventional TV channel selection methods. One method is direct channel selection for selecting a channel by operating a channel button to select the assigned channel, and the other method is sequential channel selection for switching a channel in turn to the neighboring channel in the order of channel numbers.
Normally, since the channel numbers of TV channels correspond to specific broadcast stations, the user who makes the direct channel selection of a specific channel selects a channel for the purpose of viewing a broadcast program. Likewise, when a slide show is to be started by direct channel selection, the user operates a channel button to which designation of an image data group is assigned for the purpose of starting the slide show.
On the other hand, the sequential channel selection is an operation for sequentially switching channels arranged in advance based on channel numbers or the like, and determining by viewing the displayed video if a broadcast program that the user wants is displayed. When the channel that starts a slide show is selected during such operation, the user feels something is wrong unlike a case wherein he or she makes the sequential channel selection in a sequence of only broadcast channels. That is, since a video of a broadcast program displayed in a broadcast channel is a moving image, and its display contents change in a short period of time, the user can receive information that allows him or her to recognize the contents of the broadcast program. By contrast, since the slide show is configured based on still image display, the information which can be obtained in a short period of time is considerably smaller than the video of the broadcast program, and the user cannot easily recognize the type of an image data group, the slide show of which is to start. When the user cannot determine based on the first image at the beginning of the slide show if a target image data group is selected, he or she must wait until the current image is switched to at least the next image while the still image that provides no more information is kept displayed.
For this reason, when a channel for starting a slide show is set among broadcast channels, the user has considerably different experiences in the sequential channel selection between a channel which displays a broadcast program and that which displays a slide show. Also, so-called zapping for seeking a channel that makes target display while sequentially switching channels cannot be smoothly made.